Prior art automated fiber placement systems which have a dockable lay up head have certain disadvantages. These systems are designed with the creel assembly integrated with the lay-up head or integrated into the last motion axis of the manipulator. When exchanging one layup head for another, such systems require the entire creel assembly to be exchanged, and in some cases, an entire motion axis must be exchanged as well. As a result, each dockable mechanism includes the additional cost of the redundant creel assembly including tension control mechanisms, material spool chucks, motors, cables, fiber delivery components, and associated structures.
For prior art systems with the creel integrated into the last motion axis of the manipulator, the dockable mechanism includes the cost of the items above, plus the additional cost of the redundant motion axis i.e. motors, bearings, gear boxes, cables, and associated structures.
Prior art systems with the creel integrated into the lay-up head or last motion axis have large structures such as the material spools and the fiber delivery components included with the head, and this gives the head a large outer profile. The large profile limits the ability of the head to lay-up on tightly contoured and/or smaller-sized parts.
Prior art systems with the creel integrated into the lay-up head or last motion axis require the last or second-last axes of the machine to support additional large masses. The larger structure and drive components required to accommodate the larger masses cause a cascade effect, with each upstream axis needing to be more robust in order to accommodate the larger loads placed on it. The secondary effect of the increased weight is increased cost resulting from the larger motors, gearboxes, bearings and structures required throughout the machine.
In order to minimize the size of the creel assembly which is integrated into the head or last motion axis, prior art systems often utilize material spools that are smaller than the industry standard. This results in the need to interrupt production more frequently in order to replenish the material supply. Further, in order to minimize the size of the creel assembly which is integrated into the head or last motion axis, the currently available systems often limit the number of material spools to a maximum of 16 instead of the more normal 32. This results in a narrower bandwidth per course of material applied to the workpiece, thereby reducing productivity and increasing the duty cycle of the system.
It would be desirable to provide a fiber placement machine with a dockable head that does not have a creel integrated into the last motion axis of the manipulator, or into the head.